Levich Institute Seminar Announcement, 01/30/2007
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Professor Michael Booty
Mathematical Sciences Department
New Jersey Institute of Technology
(Currently on Sabbatical at CCNY)
"Steady and Tip-Streaming Solutions of a Slender Surfactant-Coated Bubble in an Extensional Flow"
Slender body theory is used to find the steady deformation and time-dependent evolution of an axisymmetric inviscid bubble in a zero-Reynolds-number extensional flow when insoluble surfactant is present on the bubble surface.
The solutions show steady ellipsoidal bubbles that are completely covered by surfactant and, at increasing strain rate, solutions that are surfactant-free on a central cylindrical part with semi-ellipsoidal surfactant-covered end caps. Simple expressions are found for the steady-state response relation between the capillary number and the bubble slenderness ratio, which show the presence of a finite critical capillary number (and hence a finite critical imposed strain rate) above which the steady solutions cease to exist. Simplified equations are shown that describe time-dependent behavior reminiscent of tip-streaming when the capillary number is above critical.
Recent results are described indicating how effects such as interior bubble viscosity or solubility of surfactant in the exterior bulk flow can modify the solution structure.
BRIEF ACADEMIC/EMPLOYMENT BACKGROUND: